The single-serve coffee market has experienced significant growth over the past 25 years with over tens of billions of single-serve coffee units sold annually worldwide. Single serve pods are very popular due to the extreme convenience of brewing a fresh, full cup of coffee in a minute or less, at the touch of a button. Despite the growing adoption and use of single serve coffee appliances and pods, there is very little literature which explores the coffee extraction kinetics at the time scales of a single serve brew method, specifically 5 to 30 s.
This thesis develops a new method for measuring early time scale coffee extraction kinetics in a well-mixed batch reactor. This is accomplished by the unique sampling approach to fractionate coffee extract at previously unachievable time scales. Coffee extraction kinetics for caffeine, chlorogenic acid (3-CQA), citric acid, malic acid, and quinic acid are measured between 5 s and 600 s with 80% of the extraction data collected under 35 s.
Individual chemical compounds with nearly identical molecular weights had very different extraction kinetics in the first 30 s. Two compounds, caffeine and 3-CQA, showed a 3 to 4 s delay in extraction. For the three other compounds, extraction began immediately. This is the first data set to capture this behavior. 50% of the citric and malic acid concentration was found to extract within the first 10 s, highlighting the criticality of understanding extraction kinetics at early time scales.
